Add --python-path, --pip-path, --gradio-path CLI arguments to let custom component developers control which executable is used

[freddyaboulton]

Description

Closes: #7621

Adds CLI arguments to let developers control the path of the python executables used in create, dev, and build commands.

Also adds some debugging information to dev mode in case no custom components are found. I suspect this will help debug issues like #6821

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Install Gradio from this PR

pip install https://gradio-builds.s3.amazonaws.com/595361c1c31ce4e9725c25c31baaed0040233f6b/gradio-4.20.1-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@595361c1c31ce4e9725c25c31baaed0040233f6b#subdirectory=client/python"

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gradio	patch

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Add --python-path, --pip-path, --gradio-path CLI arguments to let custom component developers control which executable is used

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[abidlabs]

Nice @freddyaboulton! Just to understand, when would one use --gradio-path?

[freddyaboulton]

We used to use which to determine the path of the gradio executable so we could launch the demo in reload mode, e.g. gradio demo/app.py. But it's possible that it picks up the wrong version of gradio if multiple versions of gradio are installed in the same system. So I'm adding a CLI argument to let developers take control if something goes wrong.

[abidlabs]

Thanks @freddyaboulton for this PR! While I think this is a working solution, it seems like a bit of a headache for the user to have to find and pass in the path to their Python for the CLI commands, particularly as they need to do it for each gradio cc command. We can add these arguments, but could we also handle the default case better:

What if we resolved pip in this order:

• the pip_path cli arguments, if provided, otherwise:
• which("pip3") if exists, otherwise
• which("pip") if exists, otherwise
• fail loudly

Same for python3 and python. I think that should make the default behavior much better for the majority of users

[freddyaboulton]

it seems like a bit of a headache for the user to have to find and pass in the path to their Python for the CLI commands, particularly as they need to do it for each gradio cc command.

I don't follow. Passing in the -path parameters is not required and is only needed if whatever heuristic we have in place fails. We can also check for python3/pip3 though.

[abidlabs]

I don't follow. Passing in the -path parameters is not required and is only needed if whatever heuristic we have in place fails. We can also check for python3/pip3 though.

Sorry my earlier comment may not have been clear. I agree -- let's keep these parameters but check for python3 and pip3 as well

[freddyaboulton]

Sounds good @abidlabs ! Just pushed up that change!

[abidlabs]

Code changes look good! In my tests, --pip-path is working, but --python-path is not having any effect.

For example, I can run:

gradio cc dev --python-path abdef/asdfklasdjf

after creating a custom component and the dev server launches successfully. That's not expected, right?

[freddyaboulton]

@abidlabs I think you needed to built the js for this PR for dev mode to break in that case. But your comment made me realize we wouldn't raise a helpful error if the executable did not exist so I just pushed that up.

[abidlabs]

Ah I see, thanks I'll give this another spin

[abidlabs]

Beautiful. LGTM

[abidlabs]

Going to merge this in for the release @freddyaboulton